North Korea is threatening to cut off all dialogue with South Korea over an alleged Seoul contingency plan for the fall of the communist government.

The threat came even as Pyongyang said it accepts South Korea's long-standing offer of food aid.

A statement issued Friday by the North's powerful National Defense Commission is demanding South Korea apologize over unconfirmed news reports about the contingency plan. The NDC vows to wage a "holy war" against those who conceived the plan, including the Blue House, the headquarters of the South Korean president.

South Korea's Unification Ministry says its isolated neighbor has agreed to accept an offer for 10,000 tons of corn that South Korea first offered in October.

Tensions between the Korean rivals have grown since conservative South Korean President Lee Myung-bak took office in 2008, vowing a tougher approach towards Pyongyang.

North Korea has made a series of overtures towards its democratic rival in recent days. Pyongyang made an offer Thursday to hold talks on resuming tourism projects that have been suspended since 2008.

The two sides will also meet next week to discuss developing Kaesong, where North Korean workers make goods in South Korean-run factories.